This invention relates in general to wheelchair seats and more particularly, to wheelchair seat cushions that reduce pressure point concentrations against the contacting portions of a user's body.
Medical practitioners have long known that excessive contact pressure against a user's body over a period of time may create a harmful condition for the user's skin. This condition is especially true where a user is confined to a wheelchair creating prolonged contact with the user's trochanters or the bony prominences of the user's buttocks. When seated, the user's weight must be properly distributed in order to reduce the pressure on the bony prominences of the user's buttocks. Resilient seat cushions are often employed to increase the supporting surface exposed to the user. Fluid, air, foam and other types of resilient cushions are used to minimize the pressure on the bony prominences.
Many resilient seat cushions lack enough support, when used alone, to prevent the user's weight from excessively compressing, or bottoming out, the cushion. Seat cushion bases, often structured as foam bases, may include a pelvic loading area (PLA) to provide better support and stability to the user. Support is improved by directing load to the tissue supporting the user's trochanters. The PLA of the foam base may be formed with sloped walls to locate a seat cushion insert. Sloped walls may help to distribute the load between the user's ischial tuberosities (IT) and trochanters. Because of the sloped walls, however, it may be difficult to place an insert into the PLA without overlapping or folding of the insert. Thus, it would be desirable to provide a seating system that improves the support and load distribution of a user's weight.